Random crashes on a new PC

you didnt mention the psu.
memtest the ram
set the bios to default?
no excessive temps in the oc?
could just have exposed a flaw somewhere , try reseating everything? try safe mode to see if its driver related?

Reinstall the graphics drivers - uninstall the old one first.

Often when the system hangs it corrupts the graphics drivers in the process ... or as a result of the driver hanging itself.

monitor your temps when you reboot it and under a decent load - encode something to load it up.

See if that has anything to do with it.

If it is under warranty then don't go messing with the hardware if you suspect something - take it back to them first.

Thank you for the suggestions.

The PSU is a 600W Cooler Master

I'd been running memtest and prime95 (both small and balanced tests). At full load, the CPU gets to 59 deg C (when overclocked to 3.4ghz). The only time memtest had come up with anything was when i was running at 1066. After I had switched to 800, there has been no issues with the tests, including the one I ran for 12 hours last night.

Prime95 also does not show any errors for an extended period of time unless I increase the FSB a few mhz. I managed to run at 3.4ghz for roughly 16 hours without a freeze.

I actually had just reset everything, namely by doing a bios upgrade. The bios version I was running was a beta upgrade, but they had just released a legit one.
The only other thing I didn't mention was that I'm running a Raid 0 with 2x 74GB Raptors.

I'd love to return the part that is causing the issue. As of now, I'm not really sure what is actually causing the problem.

Thank you for your help in my brainstorm, and keep the ideas coming.

I didn't need to manually reverse everything. When I did the last BIOS upgrade, it reset all of the settings. This time, the only thing I configured was my raid setup - Not changing any other settings. It has been stable for a day so far with the new BIOS, so we'll see what happens. Like I said before though, the last freeze took 2 days.

Try running cpuz to check the speeds and voltages.

1) ungang the memory controllers ?

2) disable spread spectrum ?

Have you gone into Computer Management / Event Viewer / System and taken a look at what fatal errors are being thrown up?

Right click My Computer and go to Manage first.

1) The K10 arch utilizes a 128-bit (2x64-bit 'ganged') memory controller. It's faster but less stable. If you 'ungang' the memory controller it will operate in '2x64-bit' mode, your performance will be marginally less, but much more stable. There is a setting in the BIOS.

2) The different components of a computer run at different clocks based upon the 'pulse' of a crystal. These different clock pulses or 'signals' may generate *EMI* or electro-magnetic interference. 'Spread spectrum' when enabled is used to modulate or 'flatten' the interference.

It is highly doubtful you have an EMI problem. Spread spectrum can really screw up system timings. You should disable spread spectrum in the BIOS for optimal system stability and performance.

I believe the Phenom II 940 does not officially support 4XDDR2-1066 configurations. Additional northbridge voltage may help, but I'm not sure.

I think Xantulle has a series of problems - first being the 2x2Gb of OCZ HPC Reaper. If I recall it needs at least 2.2v-2.3v at 1066MHz (not sure of the timings). If the mobo defaults to JEDEC SPD he is way off.

I don't mean to dawg OCZ but I also suspect that the RAM may simply be over-volted DDR2 800 with reduced timings.

Maybe Memtest would help him.

Don't know about electrodon - either we fixed his problems or 'exploded' it

I am also having problems with a Phenom II and 2 sticks of DDR2-1066. Random crashes and blue screen having to do with memory issues or oddball files. When the ram is set to 800, no problems at all. A technician from G.Skill posted the settings for the RAM & my board, so I used them and still have issues. The last thing to try is the spread spectrum before I'm out of ideas.

BFG 650watt PS
Gigabyte MA-790X-UD4P
Phenom II X3 720 Black
GSkill 5-5-5-15 @ 2.1 V
WD Caviar Black 500g HD

I thought it was an overclocking thing, but I run into problems at stock speeds too, if I let the RAM set itself, or if I use the recommended settings. I'll let you know if the spread spectrum works

UR31337

Did you download and check the RAM settings on CPUZ?

I may try that as well. I just don't see how a simple browser could be my problem. Has firefox ever been known to cause hard lock-ups?

I just set up my system:
M4N78 Pro
Phenom 9600
Ultra 500W, etc. etc.

I was having no problem with the RAM I initially had, which was the OCZ Blade 1066 (I should add that I was running it at 800). Then I switched to the OCZ Reaper 1066 and manually set the BIOS to 1066. Then I started getting crashes.

Sorry it's not a perfectly controlled experiment, since there are two variables (new RAM, different Mhz), but that might give you something to go on. Weird, though--the Reaper is on the QVL and the Blade isn't.

Thanks for the tip. Call me a noob, but I didn't know that. Any tips on how to know what kind of voltage I should be looking for with OCZ Reaper 1066 ton the M4N78 Pro motherboard?